SSALMON – The Solar Simulations for the Atacama Large Millimeter Observatory Network

Wedemeyer, Sven; Bastian, T. S.; Brajša, R.; Bárta, M.; Hudson, H. S.; Fleishman, G. D.; Loukitcheva, M.; Fleck, B.; Kontar, Eduard P.; Pontieu, Bart De; Tiwari, Sanjiv K.; Kato, Yoshiaki; Soler, Roberto; Yagoubov, P.; Black, J. H.; Antolin, Patrick; Gunár, S.; Labrosse, Nicolas; Benz, A. O.; Nindos, A.; Steffen, M.; Scullion, Eamon; Doyle, J. G.; Zaqarashvili, T. V.; Hanslmeier, A.; Nakariakov, V. M.; Heinzel, P.; Ayres, Thomas R.; Karlický, M.

doi:10.1016/j.asr.2015.05.027

Cited by 5 publications

(5 citation statements)

References 124 publications

(151 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A natural progression would be to employ multi-wavelength observations, spanning the radio domain (e.g., ALMA; Wedemeyer et al 2015) through to X-rays (e.g., Hinode/XRT; Golub et al 2007), to provide a multi-height investigation of nanoflare activity from the photosphere through to the outer corona. Even within the EUV environment sampled by SDO/AIA, the self-similar and complementary platescales and cadences may be utilized to examine the multi-wavelength, and hence multi-thermal effects associated with flaring events (e.g., furthering the work of Viall & Klimchuk 2011, 2012, 2015.…”

Section: Future Directionsmentioning

confidence: 99%

Statistical Signatures of Nanoflare Activity. I. Monte Carlo Simulations and Parameter-space Exploration

Jess

Dillon

Kirk

et al. 2019

ApJ

View full text Add to dashboard Cite

Small-scale magnetic reconnection processes, in the form of nanoflares, have become increasingly hypothesized as important mechanisms for the heating of the solar atmosphere, for driving propagating disturbances along magnetic field lines in the Sun's corona, and for instigating rapid jet-like bursts in the chromosphere. Unfortunately, the relatively weak signatures associated with nanoflares places them below the sensitivities of current observational instrumentation. Here, we employ Monte Carlo techniques to synthesize realistic nanoflare intensity time series from a dense grid of power-law indices and decay timescales. Employing statistical techniques, which examine the modeled intensity fluctuations with more than 10 7 discrete measurements, we show how it is possible to extract and quantify nanoflare characteristics throughout the solar atmosphere, even in the presence of significant photon noise. A comparison between the statistical parameters (derived through examination of the associated intensity fluctuation histograms) extracted from the Monte Carlo simulations and SDO/AIA 171Å and 94Å observations of active region NOAA 11366 reveals evidence for a flaring power-law index within the range of 1.82 ≤ α ≤ 1.90, combined with e-folding timescales of 385 ± 26 s and 262 ± 17 s for the SDO/AIA 171Å and 94Å channels, respectively. These results suggest that nanoflare activity is not the dominant heating source for the active region under investigation. This opens the door for future dedicated observational campaigns to not only unequivocally search for the presence of small-scale reconnection in solar and stellar environments, but also quantify key characteristics related to such nanoflare activity.

show abstract

Section: Future Directionsmentioning

confidence: 99%

Statistical Signatures of Nanoflare Activity. I. Monte Carlo Simulations and Parameter-space Exploration

Jess

Dillon

Kirk

et al. 2019

ApJ

View full text Add to dashboard Cite

show abstract

“…So, the measured brightness temperature is directly proportional to the gas temperature of the observed structure or layer in the solar atmosphere. Therefore, it is very important to develop numerical simulations of various solar atmosphere types as a priori and a posteriori supporting tools for solar observations with ALMA (Wedemeyer et al 2015) and to compare results with available measurements. It was clear from the initial phase that ALMA can be pointed at the Sun and that it will become an important tool if it could be made available for solar physics.…”

Section: Introductionmentioning

confidence: 99%

First analysis of solar structures in 1.21 mm full-disc ALMA image of the Sun

Brajša

Sudar

Benz

et al. 2018

A&A

Self Cite

View full text Add to dashboard Cite

Context. Various solar features can be seen in emission or absorption on maps of the Sun in the millimeter and submillimeter wavelength range. The recently installed Atacama Large Millimeter/submillimeter Array (ALMA) is capable of observing the Sun in that wavelength range with an unprecedented spatial, temporal and spectral resolution. To interpret solar observations with ALMA the first important step is to compare solar ALMA maps with simultaneous images of the Sun recorded in other spectral ranges. Aims. The first aim of the present work is to identify different structures in the solar atmosphere seen in the optical, infrared and EUV parts of the spectrum (quiet Sun, active regions, prominences on the disc, magnetic inversion lines, coronal holes and coronal bright points) in a full disc solar ALMA image. The second aim is to measure the intensities (brightness temperatures) of those structures and to compare them with the corresponding quiet Sun level. Methods. A full disc solar image at 1.21 mm obtained on December 18, 2015 during a CSV-EOC campaign with ALMA is calibrated and compared with full disc solar images from the same day in Hα line, in He I 1083 nm line core, and with various SDO images (AIA at 170 nm, 30.4 nm, 21.1 nm, 19.3 nm, and 17.1 nm and HMI magnetogram). The brightness temperatures of various structures are determined by averaging over corresponding regions of interest in the calibrated ALMA image. Results. Positions of the quiet Sun, active regions, prominences on the disc, magnetic inversion lines, coronal holes and coronal bright points are identified in the ALMA image. At the wavelength of 1.21 mm active regions appear as bright areas (but sunspots are dark), while prominences on the disc and coronal holes are not discernible from the quiet Sun background, although having slightly less intensity than surrounding quiet Sun regions. Magnetic inversion lines appear as large, elongated dark structures and coronal bright points correspond to ALMA bright points. Conclusions. These observational results are in general agreement with sparse earlier measurements at similar wavelengths. The identification of coronal bright points represents the most important new result. By comparing ALMA and other maps, it was found that the ALMA image was oriented properly and that the procedure of overlaying the ALMA image with other images is accurate at the 5 arc sec level. The potential of ALMA for physics of the solar chromosphere is emphasized.

show abstract

“…We can expect much, much more with ALMA (e.g. Wedemeyer et al, 2015); this wonderful facility can make both novel single-dish observations and also interferometric observations at unprecedented resolution.…”

Section: Solar Infrared and Sub-thz Observationsmentioning

confidence: 97%

Chasing White-Light Flares

Hudson

2016

Sol Phys

View full text Add to dashboard Cite

In this memoir I describe my life in research, mostly in the area of solar physics. The recurring theme is "white-light flares," and several sections of this paper deal with this and related phenomena; I wind up describing how I see the state of the art in this stillinteresting and crucially important (as it has been since 1859) area of flare research. I also describe my participation in two long-lived satellite programs dedicated to solar observations (Yohkoh and RHESSI) and elaborate on their discoveries. These have both helped with white-light flares both directly and also with closely related X-ray and γ -ray emissions), with the result that this article leans heavily in that direction.

show abstract

SSALMON – The Solar Simulations for the Atacama Large Millimeter Observatory Network

Cited by 5 publications

References 124 publications

Statistical Signatures of Nanoflare Activity. I. Monte Carlo Simulations and Parameter-space Exploration

Statistical Signatures of Nanoflare Activity. I. Monte Carlo Simulations and Parameter-space Exploration

First analysis of solar structures in 1.21 mm full-disc ALMA image of the Sun

Chasing White-Light Flares

Contact Info

Product

Resources

About